Goodwill and Other Intangible Assets - Schedule of Changes in the Carrying Amount of Goodwill by Segment (Details) $ in Millions	9 Months Ended
	Sep. 30, 2018 USD ($)
Goodwill [Line Items]
Goodwill net book value, beginning balance	$ 447.4
Disposition	(9.3)
Foreign exchange and other adjustments	(0.6)
Goodwill net book value, ending balance	437.5
U.S.
Goodwill [Line Items]
Goodwill net book value, beginning balance	429.2
Disposition	(3.5)
Foreign exchange and other adjustments	0.0
Goodwill net book value, ending balance	425.7
International
Goodwill [Line Items]
Goodwill net book value, beginning balance	18.2
Disposition	(5.8)
Foreign exchange and other adjustments	(0.6)
Goodwill net book value, ending balance	$ 11.8